Mr Ray Purchase offers an alternative view of the High End. (Part #2 of 2)

22 November 2017

Solid State and Active are Clean

I don't think it is too controversial to claim that solid state amplification suffers less from distortion than valve, can have higher reserves of power, lower output impedance, flatter frequency response and so on.

Nor is it controversial to claim that active speakers <a href="http://en.wikipedia.org/wiki/Powered_speakers”>distort less</a> than passive systems, for myriad reasons including the reduced 'distortion' of phase shifts and poor transient response. In every way they can be argued to be better, and hugely reduce the demands on their multiple amplifiers. An amplifier's sound is inextricably linked to the load, and by going active we can make life very easy for it and effectively make it transparent.

By going fully digital and embracing DSP crossovers, we can correct many of the physical shortcomings of the transducers to any degree we choose, including optimising the impulse response for the listening room.

Most audiophiles will never have heard such a system, and therefore cannot conceive of the improvement to stereo imaging that is possible, as well as striking improvements in all other areas.

Still tweakable

Objections to digital/active systems include the complexity of setting up what can end up as something of a Heath Robinson system which is in danger of blowing up your precious drivers. Or the opposite: that there is nothing to 'tweak'.

I could envisage solutions to both these problems. Such solutions probably already exist, but aren't widely known. For me, the perfect system would be as follows:

An attractive single box that takes in digital audio (from PC, CD player etc.) and gives me two, three or four pairs of analogue output channels from phono sockets, each of which has a hardware level pot. It has an overall volume pot with remote control. The box guarantees to never do anything nasty at power off and on. Maybe it has a few simple buttons and LEDs to select presets etc., but I would prefer a simple USB interface (or wireless link to a tablet etc. - but getting too hung up on that is veering off into non-high end territory I would suggest...) that enables me to set up anything and everything I choose in software, but can then be disconnected. The box has a phantom-powered microphone input.

The software gives me a choice of 'views' of varying complexity, and in the most complex I have complete control of impulse response correction etc. with the ability to make measurements. In the simplest view I have basic control of driver levels, delays, crossover slopes and frequencies and, I suggest, one of the most useful and intuitive controls of any speaker system: adjustable baffle step correction for each driver. An online database of presets is available for most speakers and/or drivers and these will give me basic phase and amplitude correction should I so desire it.

I can use two, three or four stereo power amps of my choice, or a single 4-, 6- or 8-channel amplifier.

I should protect my tweeters after the power amps and to do this I have a box or boxes containing my choice of audiophile-grade capacitors in series.

My speakers can be conventional multi-driver enclosures minus the crossovers and featuring four, six or eight 4mm sockets on the back, or I could even buy single drivers in single boxes à la Kef 105 for the ultimate in tweakability (if someone saw a market opportunity and started to make them).

I suggest that this setup would be easy to use, while maintaining tweakability without the fragility and lack of permanence that may be a worry with some self-assembled active systems.

Conclusion

I suggest that only by abandoning our attachment to vinyl, valves and passives can we enjoy the spectacular quality of digital recordings, with better and more accurate stereo soundstages. Vinyl recordings and passive speakers are fundamentally and arbitrarily compromised (let's not beat about the bush: when it comes to the inner tracks on an LP they are positively dirty!), and expecting cables and tweaks to magically reverse that is a dead end. Trying to harness the potential of digital audio by dropping it into systems which are only suited to the gentle demands of vinyl playback doesn't work, and only a system-wide upgrade will suffice.

My own experience with a fully active, sealed, three-way stereo speaker system using tailored DSP crossovers and digital recordings, is not only that it is staggeringly clean, musical, rich and dynamic, but that a 'sonic holography' occurs in the stereo imaging that I have never heard when using a more traditional setup. The ability of the audio system to transform the listener's environment rather than just fill his ears with sound, is enhanced. Expectations that such a 'scientific' system might sound clinical or unmusical are completely forgotten and shown up as irrational fears.

It suggests to me that there is still unused potential in the stereo format that makes multi-channel surround less necessary. Surround sound may be an easy 'hit' but in most rooms it would blur the precision that could otherwise be achieved from stereo alone using a top notch digital/active system. The fact that plain stereo is also compatible with headphones is an added bonus.